What is a Sample Size Calculator?

A Sample Size Calculator helps you determine the number of people you need to survey for reliable results. By entering key details like population size, confidence level, and margin of error, you can calculate the ideal sample size for accurate research findings. For example, If you’re surveying 10,000 customers and want 95% confidence with a 5% margin of error, the calculator will tell you how many responses you need to ensure trustworthy insights.

What Does the Result Mean?

The sample size calculation tells you how many people you must survey to get reliable results. If the calculator suggests 400 respondents, that means surveying at least 400 people will give you statistically reliable results within your chosen margin of error. A larger sample size increases accuracy, while a smaller one may produce less precise results. Use this number to plan your survey with confidence!

Tips:
Want more precision? Lower the margin of error, but this will increase the required sample size.
Not sure how many people to survey? Try different confidence levels and margin of error settings to see how they affect sample size.

Now that you have your sample size, what’s next?
Need to check how precise your results are? Use our Margin of Error Calculator to measure the accuracy of your survey.

How to Use the Sample Size Calculator

1. Step 1: Enter your Population Size – This is not the total population of a country or city. It’s the specific group you want to study (e.g. school students between the ages of 10 to 16 in the U.S.). If you’re surveying customers of a particular store, the population size is the total number of customers who shop there, not the entire city.

2. Step 2: Choose your Confidence Level – Select how sure you want to be about your results (90%, 95%, or 99%). A higher confidence means greater certainty but requires more responses to reduce errors. For example, a 95% confidence level is the standard for most surveys, but if you choose 99%, you’ll need a larger sample size for higher accuracy.

3. Step 3:  Select your Margin of Error – The range within which the true result may vary. Choose how much your results might vary from the true answer.
   ✔ Smaller margin (±3%) → More accurate results but requires more responses.
   ✔ Larger margin (±5% or more) → Less precise but needs fewer responses.
   For example, If 60% of people like a product and your margin of error is ±3%, the real number could be between 57% and 63%. A ±5% margin means it could be between 55% and 65%.

4. Step 4: View Your Sample Size – The tool will tell you how many responses you need for reliable data.

5. Step 5: Plan your survey: Use this number to ensure your research is accurate and meaningful before launching your survey.

Why Does Sample Size Matter?

Getting the right sample size is key to accurate and reliable results. Here’s why it’s important:

✔ Accuracy – Reduces errors and makes your survey results more reliable.
 ✔ Efficiency – Saves time and resources by collecting just the right amount of data.
 ✔ Trustworthy Insights – Ensures your findings reflect the whole population, not just random chance.

Want to ensure your qualitative research captures the right insights?

Explore how different approaches impact your study and discover best practices for gathering meaningful data in our expert guide on sampling methods.

Who Can Use This Calculator?

✔ Market Research and Businesses – Find the right number of customers to survey for product feedback and market trends.
✔ Academic & Social Research – Ensure studies accurately represent populations for research and policy analysis.
✔ Healthcare & Clinical Trials – Determine how many patients are needed for valid medical research.
✔ Employee & Workplace Surveys – Gather reliable employee insights for engagement and policy decisions.
✔ Government & Public Policy – Calculate voter research and census study respondents.
✔ Media & Advertising – Measure audience opinions and ad effectiveness with accurate sample sizes.

Now that you have your sample size get expert insights to maximize your survey’s design.
We provide in-depth insights to drive better decisions as a leading market research agency.

Contact us today to discuss your research needs!